Merf

Merf is listed in the Furry Dictionary as "A sound made to show suprise or annoyance" (definition contributed by Luphinus in October 2000)or a "(verb) To talk or chat (normally associated with vulpines and other canids)" (definition contributed September 2000 by LionkingCMSL).[1]

Various people used the word merf when answering the Furvey, since at least 1999.